Push type writing implement

ABSTRACT

Writing implement having a button protruding out near the rear end of a barrel. Formed integrally with the button is a push rod which is slidably mounted within a guide channel inside the barrel. Inserted from front end of the barrel is a length of writing medium which is in close contact with the said push rod. By pushing the button, the wriging medium is forced to protrude in front of the implement to take a writing position.

United States Patent Kao 1 Dec. 2, 1975 [541 PUSH TYPE WRITING IMPLEMENT 572.105 12/1896 Cummings Ct 211. 401/65 I 726 767 4/1903 Schemnitzky I. 401/84 [76] lnvemor- W g- Kao, 4 LO 2,405.79? 2 1946 Plut 401/82 L1, Ta1t0ng Town, Taltong, Chma/Tawan Primary E.\'aminer-Lawrence Charles [22] Filed: Mar. 15, 1974 [57] ABSTRACT [2]] Appl' 451540 Writing implement having a button protruding out near the rear end of a barrel. Formed integrally with [52] US. Cl. 401/82 the button is a push rod which is slidably mounted [51] Int. Cl. B43K 21/10 within a guide channel inside the barrel. Inserted from [58] Field of Search I. 401/81-84, front end of the barrel is a length of writing medium 401/88, 90, 57, 80 which is in dose contact with the said push rod. By pushing the button, the wriging medium is forced to [56] References Cited protrude in front of the implement to take a writing UNITED STATES PATENTS Position- 276,659 5/1883 Birch 401/83 X 8 Claims, 6 Drawing Figures US. Patant Dec. 2, 1975 PUSH TYPE WRITING IMPLEMENT FIELD OF INVENTION The present invention relates generally to a writing implement and more particularly to a push type writing implement. By pushing forward a button located near the rear end of a barrel, a push rod in the barrel formed integrally with the button forces a length of writing medium which is in close contact with the rod to project in front for writing.

BACKGROUND OF INVENTION Writing implements such as pencils, sharpening of which is quite a tedious work, as well as non-sharpening pencils with pre sharpened lead being displaceable in small cartridge form have been known. However, the frequent discard of the blunt lead constitutes a waste. Therefore, a writing implement with an adjustable writing medium has a favorable competative position.

A writing implement with an adjustable writing medium or core usually comprises a screw means inside a barrel and a core seat that moves in the longitudinal direction using the screw means as a guide. In using such a kind of implement both hands of the user has to be applied simultaneously to operate it. This is quite inconvenient.

In view of this, the present inventor has provided a novel kind of writing implement to overcome the above drawback.

SUMMARY OF INVENTION Therefore, the main object of the present invention is to provide a writing implement such that with just a push of the finger the writing medium projects in front of the barrel for use.

Another object of the present invention is to provide a novel writing implement having a simple construction with a few parts which can be moulded from plastic material, whereby the cost is so low that it facilitates mass production.

Further objects and features of the present invention will become apparent from the following detailed description to be taken in conjunction with the annexed drawings.

' BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows a preferred embodiment of the push type writing implement of the present invention in assembled form with the barrel cut away to see the inside construction;

FIG. 2 is an exploded view of the same embodiment showing the details of the parts.

FIG. 3 shows the implements longitudinal sectional view FIG. 3A shows a cross-sectional view of the implement FIG. 4A shows writing medium of round crosssection being applied; and

FIG. 4B shows writing medium of triangular crosssection being applied.

DETAILED DE SCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, the writing implement of the present invention comprises a barrel 1, push rod 2, end socket and eraser assembly 3, and writing medium (or lead core, if it is a pencil) 4.

Barrel 1 has a conical front end. Passing through the center of barrel 1 is a channel 14 having a cross-section resembling that of the core in the present embodiment which is triangular since a stick of lead core of triangular cross-section is being used. The barrel has front exit 15. In parallel with the channel 14 and on top thereof is a guiding channel 11 for push rod 2. The front end of the channel 11 is tapered in conformance with the conical head of the barrel and is numerically marked as 11. Channel 11 has at its rear end a push rod base seat 12.

Referring to FIG. 3, push rod 2 comprises rod 21 which is of rectangular cross-section having a wedgelike front end 22 inclined just like that of channel front 1 l. The cross-section of channel 1 l is also in rectangular form but with a height higher than that of rod 21. The clearances between the sides of rod 21 and channel 11 are quite small which allows rod 21 to slide longitudinally and float up and down. The under side of the rod 21 has a rough surface 28 somewhat like the surface of a file to enable sufficient friction to develop with the surface of the core 4.

At the rear end of push rod 2 is a base 24. Between base 24 and rod 21 is formed integrally a V type spring 23. Upon assembling, base 24 is to be retained in the seat 12 and rod 21 inserted into channel 11. A wedgetype projection 27 on base 24 fits into a wedge shaped cavity 13 of the seat 12 without vibration.

When push rod 2 is assembled into barrel 1 a front arm 25 of the V type spring 23 protrudes out to form a button. Spring 23 biases the under surface 28 of rod 21 constantly into contact with the upper surface of core 4. A notch 26 is formed in front of arm 25. The spring 23 presses the notch 26 to engage a cut-out portion 16 of barrel to prevent the core 4 from slippage. When a finger of the user snaps the arm or button 25 backwardly against the bias of spring 23 notch 26 disengages from the cut-out portion 16. Rod 21 then floats up and releases the core 4 which may then be slid freely within channel 14. The projection of core 4 may also be accomplished by pushing forward frequently the arm or button 25 to a desired length. The core 4 may then be locked by engaging notch 26 with cut-out portion 16. When not in use, disengage notch 26 and cutout portion 16 and hold barrel up side down. The core 4 would then retract into the barrel.

At the rear end of barrel 1 a socket 31 is provided to prevent base 24 from slipping out of seat 12. Eraser 32 is mounted at the rear end of socket 32.

Now refer to FIGS. 4A & 4113 showing that cores of various cross-sections may be used. While core 4 is of triangular cross-section, core 4' is of round crosssection. Whatever the cross-section of the core might be, since channel 14 has a triangular cross-section, the core will always be gripped firmly within the channel. If it is necessary, the inner surface may be roughed up to get a better effect.

The implement related herein is not limited to a pencil. The core may be crayon, chalk, felt or even for cosmetic purposes. The above embodiment is given only for illustrative purpose and not by way of limitation and modification will become evident to those skilled in the art which will fall within the scope of attached claims.

I claim:

1. Push type writing implement comprising a barrel to contain a core of writing medium, a channel disposed at the center of said barrel for the said core, another channel in parallel with the core channel, a push rod in said other channel, a seat at the rear of the barrel to retain the push rod, a V shaped spring integral with the push rod at its rear, said spring having an arm protruding outside the barrel wall to form a push button, a notch on said arm biased by said spring into engagement with a cut-out portion on the barrel wall to prevent the rod from slipping, said push rod being in contact with a core of writing medium in said barrel when said notch is engaged with said cut-out portion, and said button being movable against the spring force to disengage the notch from the cut-out portion and the push rod from the core, whereby the desired protrusion of the core from the barrel may also be effected by repeated pushing of said button. 5

2. Writing implement according to claim 1, wherein the channel for the core has a triangular cross section.

3. Writing implement according to claim 2, wherein the inner surface of the channel for the core is roughened.

4. Writing implement according to claim 1, wherein the push rod has a rectangular cross-section .with a front end tapered to conform with a conventional conical head of the barrel, the channel-for the push rod also has a rectangular cross-section but with a height greater than that of the rod, and clearances between the sides of the rod and the channel are small to permit the rod to slide only back and forth and float when released.

5. Writing implement according to claim 1, wherein the under surface of the rod is roughened to increase friction when in contact with the core.

6. Writing implement according to claim 1, wherein the rear end of the rod has a base having a wedge-like projection to be fitted firmly into a wedge-like cavity of the seat.

7. Writing implement according to claim 1, wherein the cross-section of the core is round.

8. Writing implement according to claim 1, wherein the cross-section of the core is triangular. 

1. Push type writing implement comprising a barrel to contain a core of writing medium, a channel disposed at the center of said barrel for the said core, another channel in parallel with the core channel, a push rod in said other channel, a seat at the rear of the barrel to retain the push rod, a V shaped spring integral with the push rod at its rear, said spring having an arm protruding outside the barrel wall to form a push button, a notch on said arm biased by said spring into engagement with a cut-out portion on the barrel wall to prevent the rod from slipping, said push rod being in contact with a core of writing medium in said barrel when said notch is engaged with said cut-out portion, and said button being movable against the spring force to disengage the notch from the cut-out portion and the push rod from the core, whereby the desired protrusion of the core from the barrel may also be effected by repeated pushing of said button.
 2. Writing implement according to claim 1, wherein the channel for the core has a triangular cross section.
 3. Writing implement according to claim 2, wherein the inner surface of the channel for the core is roughened.
 4. Writing implement according to claim 1, wherein the push rod has a rectangular cross-section with a front end tapered to conform with a conventional conical head of the barrel, the channel for the push rod also has a rectangular cross-section but with a height greater than that of the rod, and clearances between the sides of the rod and the channel are small to permit the rod to slide only back and forth and float when released.
 5. Writing implement according to claim 1, wherein the under surface of the rod is roughened to increase friction when in contact with the core.
 6. Writing implement according to claim 1, wherein the rear end of the rod has a base having a wedge-like projection to be fitted firmly into a wedge-like cavity of the seat.
 7. Writing implement according to claim 1, wherein the cross-section of the core is round.
 8. Writing implement according to claim 1, wherein the cross-section of the core is triangular. 